Diaphragm silencer assembly for engine muffler

ABSTRACT

A diaphragm assembly for use in providing inertial dampening and valve action in an internal combustion engine muffler includes a flexible diaphragm element which is mounted over a centrally located post in concentric relationship therewith. The central post is supported on an outer ringshaped member by means of a spider structure. The edges of the diaphragm element abut against the ring member in response to back pressure from the ambient atmosphere to effectively provide a closing action. These edges are forced away from ring member by exhaust gas pressure, thus providing opening action to permit release of the exhaust gases.

United States Patent Hoffman et a1. 1 1 Aug. 5, 1975 15 1 DIAPHRAGMSILENCER ASSEMBLY FOR 3.561.561 2/1971 Trainor 181/37 X ENGINE MUFFLER3.612.214 111/1971 B11111 et a1. 1111/37 E H H Cm d F 3.754.740 8/1973P|pcr 1 239/514 76 I t d d l 1 fi' 'g'gz g Cam FOREIGN PATENTS ORAPPLICATIONS 578.839 6/1959 Canada 219/534 1 Flledr 1973 1.251.7759/1960 France 1111/49 853.861) 11/1960 United Kingdom..... 1111/41 A[2]] Appl' 110,577 5119311 Austria. 181/47 A Relaled US. ApplicationData 754.6911 11/1933 France. 181/36 B 1972, Pat, No. 3.779.340.

[52] US. Cl 181/45; 181/64 R; 239/534 [51] Int. Cl. FOln 1/00 [58] Fieldof Search 181/36 R, 36 B, 47 A. 37. 181/57, 64. 45; Z39/S33 S34 [56]References Cited UNITED STATES PATENTS 671.523 4/1901 Zohbiller 181/371.376.263 4/1921 Emerson... .1 181/57 1.376.263 4/1921 Emerson 181/47 A1.666.005 4/1928 Culp 181/57 1.818.796 8/1931 Feyens 123/75 1,864,9156/1932 Kosterman. 181/57 2.933.148 4/1960 Hendry 181/47 A -1106.98510/1953 Recupito... 181/37 X 3.334.819 5/1967 Olavson 1. 239/5343.415145 12/1968 Yamamoto et a1. 128/147 Primary Emmi! r-Stephen J.Tomsky Ass/stun! Llmmiuer-Vit W. Miska I57] ABSTRACT A diaphragmassembly for use in providing inertial dampening and valve action in aninternal combustion engine muffler includes a flexible diaphragm elementwhich is mounted over a centrally located post in con Centricrelationship therewith The central post is supported on an outerringshaped member by means of a spider structure. The edges of thediaphragm element abut against the ring memher in response to backpressure from the ambient atmosphere to effectively provide a closingaction. These edges are forced away from ring member by exhaust gaspressure. thus providing opening action to permit release of the exhaustgases.

3 Claims. 3 Drawing Figures 31 kljhih 30f i 18 3061 a 46 a r/ I. a 1

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PATENTEU AUG 51% FIG. I

DIAPHRAGM SILENCER ASSEMBLY FOR ENGINE MUFFLER This'a pplication isa(:ontinuation in Part of our ap plication S er. N0. 296,072; filed C1.10, 1972, now U;S. Patent No. 3,779,340.

i This lt'lYEtttlOIlJ'ClfltCS to internal combustion engine mufflers andmore'particularlyto a "diaphragm assembly for use in such a muffler.

In our application Ser. No. 296,072 tiled Oct. 10. 1972, a muffler isdescribed which utilizes a diaphragm assembly having one or morediaphragm elements for providing inertial dampening and affording valveaction which greatly improves the performance of the muffler. Thepresent invention involves a diaphragm assembly which operates in thesame general manner as those described in our aforementioned priorapplication but which utilizes only a single diaphragm element with aheat shield and a somewhat different structural implementation. Thedevice of the present invention, while less effective in its silencingaction than diaphragm assemblies having a plurality of diaphragmelements. nevertheless affords the advantage of greater simplicity andeconomy of construction.

It is therefore the principle object of this invention to provide adiaphragm assembly for use in an internal combustion engine muffler ofsimpler and more economical construction.

Other objects of my invention will become apparent as the descriptionproceeds in connection with the accompanying drawings, of which:

FIG. 1 is an clevational, cross-sectional view ofa preferred embodimentof the invention as incorporated into a muffler assembly;

FIG. 2 is a view taken along the plane indicated by 22 in FIG. 1; and

P16. 3 is a plan view of the preferred embodiment of the diaphragmassembly of the invention showing the side thereof opposite to thatshown in FIG. 2.

Referring now to the figures. frame 11 includes a ring portion 12.Extending from ring portion 12, in a direction substantially normal tothe surface of the ring, is an annular lip 14. Lip 14 has a pair ofindentations 14a formed therein which are used to retain the ringagainst rotation in muffler assembly 20. Extending inwardly from ring 12are arms 17 which form a spider assembly which supports a centrallylocated ring 18. Central post 22 is supported in ring 18 by means offlanged end por tion 25 of the post assembly which is flared and pressedagainst the face of ring 18 to effectively form a retaining rivet.

Central post 22 has, integrally formed therewith. an end disc 28. Fittedover central post 22 is a flexible diaphragm element which may be madeof a suitable high temperature silicone rubber. A heat shield 31 for thediaphragm which may be of stainless steel is mounted in front of thediaphragm. This shield serves not only to protect the diaphragm from theheat of the exhaust gasses but also operates as a sound reflector whichit has been found reduces the noise level. The central portion 30a ofthe diaphragm element is widened so that it fits snuggly between disc 28and ring 18 in resilient retention therebetween. The outer portions 30bof the diaphragm element are free to move axially in response to gaspressure. In the absence of any pres sure differential, between theopposite faces thereof, the diaphragm element is resiliently retained inthe position shown in FIG. 1, with the edges thereof abutting againstring 12. Diaphragm 30 has an annular lip 30c running around theperiphery thereof which seals against ring [2 in response to pressure onthe outer surface of the diaphragm.

Diaphragm 30, further. has a plurality of apertures 30d formedtherethrough which are utilized to provide pressure relief in handlinghigh back pressures. Surrounding each of apertures 30d is a hexagonalindentation 300 formed in the surface of the diaphragm. Theseindentations serve to break up and diffuse sound waves, thus aiding inthe silencing action.

The diaphragm assembly is retained at the exhaust end of muffler 20means of an annular snap ring 40 which is retained in annularindentation 41 formed along the edge portion ofthe main body 20 of themuffler.

Exhaust gas is fed from central muffler chamber 45 through flared outlet46 to the diaphragm assembly. The exhaust pressure forces the outerportions of diaphragm element 30 outwardly with lip portion 30(' movingaway from its engagement with ring [2. The outward movement of diaphragmelement 30 is limited by disc 28 as indicated by the dotted lines. Wherethere is a back pressure. i.e. a positive pressure differential betweenthe ambient atmosphere and muffler chamber 45, the outer portions of thediaphragm element are forced inwardly with lip 30c sealing against ring12, thus alleviating noise effects incidental to such back pressureeffects. Apcrtures 30d provide pressure relief in the ease of high backpressures, thus preventing dis tortion of the diaphragm which mightresult in damage thereto. Ribs 30fmay be provided on the diaphragm tostiffen its structure.

The device of the invention thus provides a simple and economicaldiaphragm assembly for providing inertial dampening and valving inresponse to gas pressure to improve the silencing action of an internalcombustion engine muffler.

While the invention has been described and illustrated in detail, it isto be clearly understood that this is intended by way ofillustration andexample only, and is not to be taken by way of limitation, the spiritand scope of this invention being limited only by the terms of thefollowing claims.

We claim:

1. A diaphragm assembly for use in an engine muffler to provide inertialdampening and to afford valve action comprising:

a flexible circular diaphragm element having a plurality of aperturesformed therethrough to provide pressure relief for high back pressure,

a ring member having a flat faced portion and an inside diameterslightly less than the diameter of said diaphragm element,

a central post.

a spider structure for supporting said central post from said ringmember, said diaphragm element being mounted over said central post inconcentric relationship therewith, with the peripheral edges of saiddiaphragm element abutting against the flat faced portion of said ringmember,

a member attached to one end of said central post for limiting themovement of said diaphragm element in response to the exhaust gaspressure, and

means for feeding the exhaust gas received by the muffler from theengine to said diaphragm element,

surface thereof facing towards the exhaust gas for breaking up soundwaves.

3. The device of claim 2 and further including a heat shield membermounted between said diaphragm element and the means for feeding theexhaust gas thereto. said heat shield member shielding said diaphragmelement from the heat of the exhaust gasses.

e e i Its

1. A diaphragm assembly for use in an engine muffler to provide inertialdampening and to afford valve action comprising: a flexible circulardiaphragm element having a plurality of apertures formed therethrough toprovide pressure relief for high back pressure, a ring member having aflat faced portion and an inside diameter slightly less than thediameter of said diaphragm element, a central post, a spider structurefor supporting said central post from said ring member, said diaphragmelement being mounted over said central post in concentric relationshiptherewith, with the peripheral edges of said diaphragm element abuttingagainst the flat faced portion of said ring member, a member attached toone end of said central post for limiting the movement of said diaphragmelement in response to the exhaust gas pressure, and means for feedingthe exhaust gas received by the muffler from the engine to saiddiaphragm element, the outer portions of said diaphragm element beingfree to move away from said ring member in response to exhaust gaspressure, and with the edges thereof in sealing engagement against saidring in response to back pressure from the ambient atmosphere.
 2. Thedevice of claim 1 wherein said diaphragm elements have a plurality ofindentations formed on the surface thereof facing towards the exhaustgas for breaking up sound waves.
 3. The device of claim 2 and furtherincluding a heat shield member mounted between said diaphragm elementand the means for feeding the exhaust gas thereto, said heat shieldmember shielding said diaphragm element from the heat of the exhaustgasses.